

Abu-Shariah, M.I.I. 2009. Determination of cave geometry by using a geoelectrical resistivity inverse model. Engineering Geology 105(3-4):239-244, doi:10.1016/j.enggeo.2009.02.006.
Al-Zarah, A.I. 2007. Hydrogeochemical processes of Alkhober aquifer in eastern region, Saudi Arabia. Journal of Applied Science 7(23):3669-3677, doi:10.3923/jas.2007.3669.3677.
Amaya, A.G., Dahlin, T., Barmen, G. and Roseberg, J.E. 2016. Electrical Resistivity Tomography and Induced Polarization for Mapping the Subsurface of Alluvial Fans: A case Study in Punata (Bolivia). Geosciences 6(51):1-13. doi:10.3390/geosciences6040051.
Bacic, M., Libric, L., Kacunic, D.J. and Kovacevic, M.S. 2020. The usefulness of seismic surveys for geotechnical engineering in karst: some practical examples. Geosciences 10(10):1-17, doi:10.3390/geosciences10100406.
BPS-Statistics of Gunung Kidul Regency. 2021 Gunung Kidul in Figure 2021. BPS-Statisctics of Gunung Kidul Regency. 404p.
Colella, A., Lapenna, V. and Rizzo, E. 2004. High-resolution imaging of the High Agri Valley basin (Southern Italy) with electrical resistivity tomography. Tectonophysics 386(1-2):29-40. doi:10.1016/j.tecto.2004.03.017.
Cui, Q.L., Wu, H.N., Shen, S.L., Xu, Y.S. and Ye, G.L. 2015. Chinese karst geology and measures to prevent geohazards during shield tunneling in karst regions with caves. Natural Hazards 77:129-152, doi:10.1007/s11069-014-1585-6.
Dahlin, T. and Zhou, B. 2004. A numerical comparison of 2-D resistivity imaging with 10 electrode arrays. Geophysical Prospecting 52(5):379-398, doi:10.1111/j.1365-2478.2004.00423.x.
Font-Capo, J., Pujades, E., Vàzquez-Suñé, E., Carrera, J., Velasco, V. and Montfort, D. 2015. Assessment of the barrier effect caused by underground constructions on porous aquifers with low hydraulic gradient: A case study of the metro construction in Barcelona, Spain. Engineering Geology 196:238-250, doi:10.1016/j.enggeo.2015.07.006.
Gabas, A., Macau, A., Benjumea, B., Bellmunt, F., Figueras, S. and Vilà, M. 2014. Combination of geophysical methods to support urban geological mapping. Surveys in Geophysics 35:983–1002, doi: 10.1007/s10712-013-9248-9.
Google Earth. 2021. Images of Pacar Rejo village, Semanu District, Gunung Kidul Regency, Yogyakarta Special Province. Accessed on 5 August 2021.
Hussain, Y., Uagoda, R., Borges, W., Nunes, J., Hamza, O., Condori, C., Aslam, K., Dou, J. and Cardenas-Soto, M. 2020. The potential use of geophysical methods to identify cavities, sinkholes, and pathways for water infiltration. Water 12(8):1-19, doi: 10.3390/w12082289.
Loke, M.H., Acworth, I. and Dahlin, T. 2003. A comparison of smooth and blocky inversion methods in 2D electrical imaging surveys. Exploration Geophysics 34(3):182-187, doi: 10.1071/EG03182.
Martınez-Lopez, J., Rey, J., Duenas, J., Hidalgo, C. and Benavente, J. 2013. Electrical tomography applied to the detection of subsurface cavities. Journal of Cave and Karst Studies 75(1):28–37, doi:10.4311/2011ES0242.
McCormack, T., O’Connell, Y., Daly, E., Gill, L.W., Henry, T. and Perriquet, M. 2017. Characterisation of karst hydrogeology in Western Ireland using geophysical and hydraulic modeling techniques. Journal of Hydrology: Regional Studies 10:1-17, doi:10.1016/j.ejrh.2016.12.083.
Metwaly, M. and Alfouzan, F. 2013. Application of 2-D geoelectrical resistivity tomography for subsurface cavity detection in the eastern part of Saudi Arabia. Geoscience Frontiers 4(4):469-476, doi:10.1016/j.gsf.2012.12.005.
Phillips, A. C., Grimley, D. A., McGuire, M. P., Shen, J., Stillwell, A. S., Szocinski, P. and Clark, A. J. 2019. Surficial Geologic Mapping for Green Infrastructure Siting and Suitability. In Geologic Mapping Forum 2019 Abstracts (Vol. Open-File Report OFR 19-1, pp. 71-72). Minnesota Geological Survey.
Pujades, E., López, A., Ramirez, C.J., Vázquez-Suñé, E. and Jurado, A. 2012. Barrier effect of underground structures on aquifers. Engineering Geology 145-146:41-49, doi:10.1016/j.enggeo.2012.07.004.
Putra, D.P.E., Setianto, A., Keokhampui, K. and Fukuoka, H. 2011 Land Subsidence Risk Assessment in Karst Region, Case Study : Rongkop, Gunung Kidul, Yogyakarta-Indonesia. In: Mitteilungen zur Ingenieurgeologie und Hydrogeologie-Festschrift zum 60.Geburtstag von Univ.-Prof.Dr.Dr.h.c.Rafig Azzam. RWTH Aachen University, German, pp. 39-50
Rizzo, E., Capozzoli, L., De Martino, G. and Grimaldi, S. 2019. Urban geophysical approach to characterize the subsoil of the main square in San Benedetto del Tronto town (Italy). Engineering Geology 257:1-9, doi:10.1016/j.enggeo.2019.05.010.
Shah, R.A., Jeelani, G. ands Goldscheider, N. 2018. Karst geomorphology, cave development and hydrogeology in the Kashmir Valley, Western Himalaya, India. Acta Carsologica 47(1):5-21.
Sun, S., Li, L., Wang, J., Shi, S., Song, S., Fang, Z., Ba, X. and Jin, H. 2018. Karst development mechanism and characteristics based on comprehensive exploration along Jinan Metro, China. Sustainability 10:1-21, doi:10.3390/su10103383.
Surono, Sudarno, I. and Toha, B. 1992. Geological Map of Surakarta-Giritontro sheet, Java, Scale 1: 100,000. Geological Research and Development Center. Bandung. Indonesia (in Indonesian).
Vachiratienchai, C., Songkhun, B. and Weerachai, S. 2010. A hybrid finite difference finite element method to incorporate topography for 2D direct current (DC) resistivity modeling. Physics of the Earth and Planetary Interiors 183(3):426-434, doi: 10.1016/j.pepi.2010.09.008.
Widyaningtyas, C.P. and Putra, D.P.E. 2014. Subsidence Hazard Mapping in Karst Area, Semanu District, Gunung Kidul Regency, Yogyakarta Special Province, Proceedings of the 7th National Earth Seminar, 30-31 October 2014, Yogyakarta, Department of Geological Engineering, Faculty of Engineering, Gadjah Mada University (in Indonesian).
Wilopo, W., Putra, D.P.E. and Susatio, R. 2020. Aquifer distribution and groundwater geochemistry in Bojonegoro sub-district, Bojonegoro District, East Java Province, Indonesia. Journal of Degraded and Mining Lands Management 7(4):2327–2335, doi:10.15243/jdmlm.2020.074.2327.
Zhang, S., Lv, Z., Wen, Y. and Liu, S. 2018. Origins and geochemistry of dolomites and their dissolution in the middle Triassic Leikoupo Formation, Western Sichuan Basin, China. Minerals 8: 289, doi:10.3390/min8070289.
Zhou, W., Beck, B.F. and Adams, A.L. 2002. Effective electrode array in mapping karst hazards in electrical resistivity tomography. Environmental Geology 42:922-928.